Multi-fulcrum plier type wrench



.Oct. 7, 1958 c. E. HUNT MULTI-FULCRUM PLIER TYPE WRENCH Filed 001:. 25, 1956 llill I l NIn-l n+ it INVENTOR.

C/arence f. Hun) MM 21, 2 319 ATTORNE rs United Sttes Patent MULTI-FULCRUM PLIER TYPE WRENCH Clarence E. Hunt, Bow, Wash.

Application ()ctoher 25 1956, Serial No. 618,394

10 Claims. (Cl. 81-3835) This invention relates to plier type tools having a fulcrum action and more particularly to such tools having a unique pivoted jaw arrangement coupled with multi fulcrum actuation means developing gripping pressures of a high order of magnitude between the jaw faces, which pressures are realized without sacrifice of the ease and facility of action or self-adjustability thereof, with the further advantage that the jaw faces remain generally parallel to each other in opening and closing.

A primary object of the present invention involves pres- .entation of a self-adjusting, ratchet-action, plier type tool with gripping power comparable to that found in conventional locking vise-pliers, which tool nevertheless preserves the advantages of the ease of manipulation of self-adjusting pliers and further of substantially parallel jaw faces throughout the range of self-adjustment. A further related object of the present invention is to provide a tool capable of use by ratchet action while having the necessary clamping power with respect to a work element, such as a bolt to be tightened, which tool need not be unlocked or withdrawn from such work piece after each stroke, as is the case with vise-pliers or conventional wrenches, thus presenting a tool which is much speedier in restricted areas than either vise-pliers, crescent or fixed jaw open-end wrenches.

. Other objects of the present invention will be apparent from the following disclosure of typical embodiments thereof, as set forth in the accompanying drawings, wherein like numerals are used to designate like parts, and wherein:

Figure 1 is a plan view of a plier type wrench characteristic of the present invention, showing the complete wrench with the jaw arms and grip arms in relatively closed position;

Fig. 2 is a cutaway plan view, partly in cross section, showing the plier type wrench of Fig. 1 with the jaw arms and grip arms thereof in relatively open position;

Fig. 3 is a side view of the plier type wrench of Fig. 1, taken along the line 3-3 thereof;

Fig. 4 is a side view of the plier type wrench illustrated in Fig. 1, taken along line 4--4 thereof;

Fig. 5 is a detached plan view of the upper jaw arm as shown in Figs. 1 and 2, with the pivoted jaw lip removed;

Fig. 6 is a side view of the detached upper jaw arm illustrated in Fig. 5;

Fig. 7 is a bottom view of the detached upper jaw arm shown in Figs. 5 and 6;

Fig. 8 is a side view of the detached bottom jaw arm shown in Figs. 1 and 2;

Fig. 9 is a bottom view of the detached bottom jaw arm illustrated in Fig. 8;

Fig. 10 is a diagrammatic fragmentary view of the head portion of the wrench housing shown in Fig. 1, diagrammatically presenting various arrangements of the longitudinal axis of the slot means therein, as a means for varying and predetermining the leverage factor of the jaw arms characteristic of the plier type tool of the present invention; and

Fig. 11 is a fragmentary view of the head portion of a modified form of a plier type wrench, corresponding to the view of the first embodiment of the invention as shown in Fig. 1, modified to the extent of a reversal of elements forming the cam slot and pin mount for one jaw arm, such modified form involving a fixed pin in the stationary housing and elongated slot means in said one jaw arm.

Turning to a more specific consideration of the typical, and therefore nonlimitative, embodiment of the present invention as presented in Figs. 1 through 9, such plier type wrench comprises a stationary housing, generally indicated at 20. Said housing 20 in turn comprises substantially parallel upper and lower side plates 21 and 22 in part providing stationary grip arm end portions 23 and 24 having grip member 25 arranged therebetween, said upper and lower side plates 21 and 22 being removably assembled into a unitary structure by means of a bolt 26 having a head portion 27 engaging said upper side plate 21 and a threaded end portion 23 threaded into lower side plate 22 in connecting said upper and lower side plates 21 and 22. Bolt 26 also retains grip arm end portions 23 and 24 thereof against grip member 25, with the alignment and connection thereof being further maintained by rivets 29 and 30, which may have pins substituted therefor, in the event disassembly of side plates 21 and 22 is desired, as hereinafter indicated. Bolt 26 also serves as the pivot pin or axis for movable grip arm 31, also as more fully discussed hereinafter.

Between respective head end portions 40 and 41 of side plates 21 and 22 are arranged respective upper and lower jaw arms 42 and 43, in turn respectively presenting opposed jaw faces 44 and 45, said jaw face 44 being advantageously pivoted in an off-center manner to the associated jaw arm 42, such pivotal mounting being provided by pin 46 and serving to enhance the ratchet-like action of the tool in use, it being evident that the inner ledge portion 47 of jaw face 44 will be urged against ledge 48 provided on the inner extremity of jaw arm 42 when said jaw faces 44 and 45 are in pressure engagement with a work piece such as a nut and a pressure thrust is exerted downwardly against grip arm 31, as the plier type wrench is shown in Fig. 1, and that as the pressure is relaxed somewhat between grip member 25' and movable grip arm 31 the wrench can be easily ratcheted back through the return stroke (upwardly in the view of Fig. 1) for the next pressure stroke on the element being worked on. This ease in ratcheting occurs because said jaw face 44 is rotated slightly about pin 46 during the return stroke so that said inner ledge portion 47 thereof is in engagement with ledge 49 on the outer extremity of jaw arm 42. Placing pivot pin 46 beyond the center of jaw face 44 toward the free extremity of jaw arm 42 has been found further advantageous in terms of positive grip during the pressure stroke, since if said pin 46 were centrally located with respect to jaw face 44 in a manner conventional per se, there would be a decided tendency for the pivot jaw face to allow the tool to slip off the work element as a result of the downward rotational force and the increased degree of force exerted by the jaw faces on the work object during the pressure stroke. With the multi-fulcrum action of the present invention manipulating the jaws of the tool, this tendency would be further increased except for such olfcenter pivoted jaw mounting, the latter functioning to permit the pressure between the jaw faces to force ledge portion 47 of jaw face 44 firmly against ledge 48 during such pressure stroke.

Proceeding to a more detailed consideration of the unique jaw arm mounting means characterizing the present invention, jaw arm 43, which may also be termed the first jaw arm for clarity of description, is provided with a fixed pivot axis on stationary housing ends 40 and 41 by means of pivot pin 50 generally adjacent to the jaw face 45 thereof, the other extremity 51of said jaw arm 43 being connected through an arcuately movable pivot pin 52 to the corresponding extremity 53 of upper jaw arm 42. Said jaw arm 42, which can otherwise be termed the second jaw arm for clarity of description, has fixedly mounted thereon and extending theretnrough a pivot pin 55 (see Fig. 6) cooperating with angled cam slot means 56 (see Fig. 1) in head portion 40 of side plate 21 and cam slot means 57 (see Fig. 2) in side plate 22 to provide for relative movement between said jaw arm 42 and said stationary housing side plates 21 and 22, the angular disposition and action of the slot means being such that a given degree of said arcuately movable pivot pin 52 produces a lesser degree of relative movement between the opposed jaw faces 44 and 45, thereby providing a leverage factor greater than the one between the pressure exerted at jaw faces 44 and 45 as compared with the pressure applied at or adjacent to said movable pivot pin 52 to the connected extremities 51 and 53 of jaw arms 43 and 42. Also, the cam slot and pin connection of jaw arm 42 cooperates with the fixed pivot axis of jaw arm 43 to maintain jaw faces 45 features of increase in leverage and more generally parallel jaw faces throughout the range of jaw movement result from the comparatively greater length of said jaw arms 43 and 42.

From the foregoing elemental relation, it becomes evident that the degree of multiplication in leverage generated at the jaw faces can be readily predetermined and varied as desired merely by changing the angle of disposition of said slots 56 and 57 in respective side plates 21 and 22. In order to further illustrate this latter important feature of the present invention, Fig. 10 presents a fragmentary view of end of side plate 21 showing a slot 56 therein and diagrammatically indicates various positions of the axis of elongation of said slot meansfsuch axial positions being considered longitudinally of the slot. The disposition of such axis of slot 56, as shown in Fig. 1, is again for purposes of illustration, labeled axis A in Fig. 10. Should design and use considerations dictate a relative reduction in the degree of pressure exerted by the jaw faces and/ or a relative increase in the extent of separation or closure of the jaw faces as results from a given degree of arcuate movement of jaw arm connecting pin 52, the axis of slot 56 can be shifted to conform to axis B, for example, and even further increased to axis C, as desired. correspondingly, should it be desired that the leverage factor at the jaw faces be increased, the axis of slot means 56 can be placed along axis D, for example, or even axis E in predetermination of the design of the tool for a specific use.

Another related feature of the angular disposition of slot means 56 and 57 and the jaw mounting arrangement of the present invention is that the rate of closing between jaw faces 44 and 45 is decreased and the leverage exerted therebetween is correspondingly increased as said jaw faces move relatively close together. Toillustrate this feature of the invention, the axis of elongation of slot means 56 and 57 is disposed at a relatively wide angle with respect to an imaginary line between movable pivot pin 52 and jaw face 44 when the jaws are in 'a relatively open position (see Fig. 2), so that the rate of movement of jaw face 44 toward jaw face 45 on closing is then relatively rapid and, as the jaw faces proceed toward a relatively closed position (see Fig. l), the angular disposition of the axis of said slot means 56 and 57 becomes considerably more parallel to said imaginary line between jaw face 44 and movable pivot pin 52, whereupon the rate of movement of said jaw face 44 is decreased and the leverage thereof materially increased when most needed, that is when the jaw faces 44 and 45 come into pressure engagement with the work piece being gripped therebetween.

While the areuate manipulation of movable pin 52 and the connected extremities 53 and 51 of jaw arms 42 and 43 by movable grip arm 31 has been considered only generally, it will be likewise evident from the construction illustrated that a very substantial multiplication in leverage also occurs by virtue of the design and mounting of movable grip arm 31. More specifically, said movable grip arm 31 is pivota'ble about said bolt 26 and has an end configuration at the jaw arm engaging end 60 thereof providing what may be termed a notched or U-shaped surface 61 contacting and moving the connected extremities 51 and 53 of jaw arms 43 and 42, said notched or U-shaped end configuration of grip arm 31 being stepped along one inner edge thereof as indicated at 62 to permit a full degree of opening of said arm 31 and interfitting thereof with the configuration of connected extremities 51 and 53 of jaw arms 43 and 42 when the latter and the grip arm 31 are relatively open, as shown in Fig. 2.

It will be readily understood that the leverage resulting from movable grip arm '31 acting on the jaw arm connected extremities 51 and 53 and pin 52 is a direct function of the distance between the point of grip of arm 31 and the pivot axis provided by bolt 26, on the one hand, and the distance between the pivot axis provided by bolt 26 and the point of contact of notch-shaped surface 61 with connected extremities 51 and 53 of jaw arms 43 and 42, on the other hand. Particularly from Figs. 1 and 2, it is seen that this leverage ratio is approximately 3 or 4 to 1 in the embodiment shown. It will be further evident that such leverage can be further increased and varied as desired and serves as a multiplying factor on the greater than one leverage ratio provided by the jaw arm mounting arrangement. In composite, these multi-fulcrum leverages remarkably enhance the pressure applied by the tool to a work object within the normally available degree of hand pressure exerted between grip member 25 and movable grip arm 31 to the point where applicants plier type wrench, for example, is capable of use as and on jobs requiring a true wrench or vise-pliers, all without necessity of locking of the grip arms as has been normally considered necessary in comparable self-adjusting tools.

Considering collectively and more specifically the fragmentary views of jaw arms 42 and 43 as presented in Figs. 5 through 9, it will be evident that jaw arm 42 having extremity 53 is provided with an aperture to accommodate pivot pin 52, mounts pivot pin 55 in the manner indicated and is cut away as at 71 on the free extremity thereof to receive movable jaw face 44 (Figs. 1 and 2), apertures 72 and 73 also being provided to receive .pivot pin 46. I

As to jaw arm 43, illustrated in Figs. 8 and 9 in detached side and bottom views, aperture 75 is provided to receive'pivot pin 50 and aperture 76 likewise receives movable pivot pin 52.

From the foregoing consideration of a typical embodiment of the present invention, it will be additionally apparent that various modifications thereof will readily occur to those skilled in the art. Thus, for example, the pin and cam slot means illustrated as embodying pin 55 in jaw arm 42 and slot means 56 and 57 in side plates 21 and 22 find a functional equivalent in a reversal of said parts wherein the pin is fixedly mounted between said side plates 21 and 22 and said slot means is arranged at an angle in said jaw arm 42. Such modified arrangement is illustrated in fragmentary side view in Fig. 11, fixed pivot pin 80 being mounted in housing end 40 and the slot means 81 being provided in said jaw arm 42 to form the relative movement connection characteristic of the present invention. Jaw faces 44 and 45 can have substituted therefor similar work elements such as pipe-wrench jaw faces, wire cutter blades or any other generally equivalent tool involving a pressure or pinching working stroke. As to this latter feature, substitutable jaw arms having variously arranged jaw faces can be readily provided in kit form with replacement of one set of jaw arms for another merely involving disassembly of the side plates 21 and'22 by removal of bolt 26 to free pivot pins 50 and 55 (and pin 80, if present), removable pins or bolts being substituted for rivets 29 and 30 to permit such disassembly. The first set of jaw arms can then be slipped out and a selected set of jaw arms inserted, and the tool reassembled. When substitutive pairs of jaw arms are employed in this manner, and when cam slot means is provided in one jaw arm (as at 81 in Fig. 11) then the angular disposition of the axis of elongation of the slot means can be particularly related to the particular type of jaw faces provided. Thus, for example, when the jaw faces are of the pipe-wrench type the maximum leverage necessary at the jaw faces will normally be greater than necessary for jaw faces of the type illustrated, and the relative angular disposition of the axis of elongation of the jaw arm slot can be reduced accordingly.

While advantageous to have the stationary housing provided with at least one removable side plate for ready disassembly of the tool, it will be evident that stationary housing 20 alternatively can be of unitary construction and that such movable grip arm and/or housing can have any desired surface or configuration, such as ribbed or knurled, for ease of gripping by the user.

Similarly, the external configuration of the various elements forming the tool may be varied within the skill of the art to produce any given maximum or minimum spacing between the jaw faces, any desired contour and appearance, and meet any considerations of weight and strength deemed necessary.

Other variations and modifications of the present invention will be apparent to those skilled in the art, within the scope of the following claims.

What is claimed is:

l. A tool comprising a stationary housing providing at one end thereof a grip member and having at the other end thereof a pair of jaw arms, each such jaw arm having an extremity pivotally connected to the other and each having at the free extremity thereof a jaw face opposing the jaw face of the other, one of said jaw arms being attached to said stationary housing by a fixed pivot adjacent to its jaw face, the pivotedly connected extremities of said jaw arms being arcuately movable with respect to said fixed pivot and said stationary housing, the second of such jaw arms being generally centrally connected to said stationary housing by cam means providing from a given degree of arcuate movement of said jaw arm connected extremities a lesser degree of relative movement between said opposed jaw faces to develop a leverage factor greater than one between pres sure exerted by said jaw faces and pressure applied at said connected extremities of said jaw arms, and means for arcuately moving said jaw arm connected extremities.

2. A tool according to claim 1, wherein said means for moving said jaw arm connected extremities comprises a movable grip arm having a fixed pivotal mounting on said stationary housing, a hand grip at the free end thereof, and a notch configuration at the other end thereof,

said notch configuration spanning said jaw arm connected extremities.

3. A multi-fulcrum tool according to claim 1, wherein one of said jaw faces is provided with a lip portion pivotally mounted to the free extremity of the associated jaw arm, the axis of such pivotal mounting being offcenter on said jaw face located toward the end tip thereof, thus facilitating a ratchet-like action of the tool in use.

4. A self-adjusting tool comprising a stationary housing providing at one end thereof a grip member and having at the other end thereof a pair of jaw arms, each such jaw arm having an extremity pivotally connected to the other and each having at the free extremity thereof a jaw face opposing the jaw face of the other, one of said jaw arms being attached on said stationary housing by a fixed pivot pin adjacent such jaw face provided thereon, the pivotally connected extremities of said jaw arms being arcuately movable with respect to said fixed' pivot pin and said stationary housing, the second of such jaw arms being generally centrally connected with said stationary housing by cam means, such cam means comprising a pin movable in elongated slot means, the angle of said slot means elongation providing from a given degree of arcuate movement of said jaw arm pivotal connection a lesser degree of relative movement between said opposed jaw faces to develop a leverage factor greater than one between pressure exerted by said jaw faces and pressure applied at said movable pivot axis, and compound leverage means for arcuately moving said movable pivot axis.

5. A self-adjusting tool according to claim 4, wherein said means for moving said jaw arm movable pivot axis comprises a movable grip arm having a fixed pivotal mounting on said stationary housing, a hand grip at the free end thereof, and a notch configuration at the other end thereof, said notch configuration extending to the opposite sides of said movable pivotal axis.

6. A multi-fulcrum, self-adjusting tool according to claim 5, wherein one of said jaw faces is provided with a pivotally mounted lip portion with the pivot point thereof arranged in an off-center manner towards the free extremity of said jaw arm, thus facilitating a ratchet-like action of the tool in use.

7. In a plier-type wrench having a stationary housing with a grip member at one end and self-adjusting work part engaging jaw means at the other end thereof, the combination wherein said jaw means comprises a first jaw arm, a first jaw face on one endof said first jaw arm, a fixed pivot pin anchoring said first jaw arm to such stationary housing adjacent said first jaw face, a second pivot pin movable with respect to said stationary housing and connecting the other end of said first jaw arm with one end of a second jaw arm, a second jaw face of the other end of said second jaw arm arranged to oppose the face of said first jaw arm, cam means acting between said second jaw arm and said stationary housing, the said cam means comprising a pin and surrounding elongated slot means, the disposition of the axis of the elongation of said slot means with respect to said pin being such that a given degree of arcuate movement of said second, movable pivot pin produces a lesser degree of relative movement between said first and second jaw faces, thereby providing increased pressure between the said jaw faces as compared with the pressure applied to the said second movable pivot pin, and means for arcuately moving said second, movable pivot pin with respect to said stationary housing.

8. A tool according to claim 7, wherein the axis of elongation of said slot means is exposed at a relatively wide angle with respect to an imaginary line between said second, movable pivot pin and the jaw face on the said second jaw arm when said jaw faces are in relatively separated position, and such angle of slot means axial disposition is decreased as the jaw faces proceed to a References Cited in the file of this patent UNITED STATES PATENTS Arbogast June 17, 1924 Davis Mar. 17, 1931 Ericsson Mar. 14, 1939 FOREIGN PATENTS .Norway Feb.'5, 1912 Germany May 21, 1953 

